Key Terms
Smooth surface (mirror)
All parallel incoming rays reflect at the same angle; only observers at that specific angle see the reflected light. Tha
To find speed in a medium
V = c / n To find n from Snell's law: n2 = (n1 * sin(theta1)) / sin(theta2)
Formula
Sin(theta_c) = n2 / n1
How it works
Light enters the fiber and hits the inner wall at an angle greater than the critical angle; it reflects completely and c
Cladding
Each fiber is coated with a material having a lower n than the fiber core. This ensures total internal reflection even w
Applications
Telecommunications (phone, internet, cable TV), endoscopes (medical imaging inside the body), laser surgery delivery.
Key pattern
N increases as wavelength decreases. Violet light (short wavelength) bends more than red light (long wavelength) when pa
Rainbow order from bottom to top
Violet, blue, green, yellow, orange, red. (Violet bends most; it ends up at the lowest angle relative to the observer.)
Converging lens (convex)
Thicker in the center; bends parallel rays toward the focal point on the far side. Focal length and power are positive.
Diverging lens (concave)
Thicker at the edges; bends parallel rays away so they appear to come from a focal point on the same side as the incomin
Focal point (F)
Where parallel rays converge (converging lens) or appear to diverge from (diverging lens) Focal length (f): distance fro
Concave (converging) mirror
Center curves toward you; focal length positive. Reflects parallel rays through the focal point in front of the mirror.
Convex (diverging) mirror
Center curves away from you; focal length negative. Reflects parallel rays so they appear to come from a focal point beh
Index of refraction
N = c / v Speed in medium: v = c / n Snell's law: n1 * sin(theta1) = n2 * sin(theta2) Crit
Lens/mirror equation
1/do + 1/di = 1/f Magnification: m = -di / do = hi / ho Power of lens: P = 1 / f (f in meters, P in d